This application claims benefits of Japanese Patent Applications No. 2004-194586, No. 2004-196729, No. 2004-202375 and No. 2004-239190 filed respectively on Jun. 30, 2004, Jul. 2, 2004, Jul. 8, 2004 and Aug. 19, 2004, the contents of which are incorporated by the reference.
The present invention relates to a transporter/sorter and a transporter box, more particularly, to a transporter/sorter for transporting and sorting transport articles as large-size home-distributed envelopes and a transport box to be used with such transporter.
Up to date, documents, magazines, books, CD cases etc., are sent as home-distributed mails and post mails.
The documents, magazines, etc. that are sent are accommodated in large vinyl or paper envelopes or cardboard or thick paper cases for home distribution or post mails. Sometimes, magazines or the like are sent without being accommodated in envelopes or cases but by merely bound with strips or in the bear state.
Large-size envelopes and cases as noted above (including post cards and small envelopes) are sorted by special transporters/sorters.
A prior art transporter/sorter (for transporting and sorting post cards or small envelopes) will now be described with reference to drawings.
FIGS. 22(a) and 22(b) are schematic views showing such a prior art transporter/sorter, FIG. 22(a) being a plan view and FIG. 22(b) being a front view. FIG. 23 is a schematic enlarged view showing a part E in FIG. 22(a). FIG. 24 is a schematic enlarged-scale view taken from F in FIG. 23.
As shown in FIGS. 22(a) and 22(b) to 24, the prior art transporter/sorter 500 comprises a frame 510, a guide rail 550 provided inside the frame 510 and in the form of an endless loop having straight and curved portions, a plurality of transport wagons 530 supported on the guide rail 550 for traveling in circulation along the endless loop path, and transport boxes 520 each suspended from each transport wagon 530.
The transport wagons 530 are coupled for revolution via joints 5131 inserted in the perpendicular direction (see FIG. 23).
The transport wagons 530 and the joints 5131 constitute a chain conveyor 560. With rotation of sprockets (not shown) that are provided on the chain conveyor 560, the transport wagons 530 are caused to undergo excursion inside the guide rail 550.
The transport boxes 520 have a shape of a substantially rectangular box. Each transport box 520 is provided, on a side face of the outer side of the guide rail 550, with an accommodating port (not shown), through which a transport article 5101 is fed (i.e., thrown) and, on the bottom, with a rotary bottom lid (not shown into) for discharging the transport article 5101.
The transport boxes 520 are hung from alternate ones of the coupled transport wagons 530 (see FIG. 24). Each transport box 520 is supported such that, in top view, gravitational center is found substantially right underneath the guide rail 550. More specifically, in the top view, the transport box 520 is supported such that its outer half is found on the outer side of the guide rail 550 while its lower half is found on the inner side of the guide rail 550 (see FIG. 23).
The frame 510 includes a plurality of section frames 5111 and a feeder frame 5112 (see FIG. 22).
The section frames 5111 each has a plurality of stackers 5113, in which transport articles 5101 discharged from the transport boxes 520 are stacked. The feeder frame 5112 has a feeder 513 for feeding transport articles 5101 via the belt to the transport box 520.
Generally, the stackers 5113 and the feeder 513 are disposed in a straight transport part of the transport box 520.
The operation of the transporter/sorter 500 will now be described.
Transport articles 5101 (i.e. postal matter, mainly post cards and small envelopes) are transported one by one from the feeder frame 5112 via the belt 514 to the feeder 513. Then, each transport article 5101 is thrown into a predetermined transport box 520 by the feeder 513.
The transport boxes 520 are transported at a constant speed by a drive means (not shown) for moving the chain conveyor 560. In the transporter/sorter 500, as shown in FIG. 23, the transport boxes 520 are spaced apart at a constant pitch (pitch L3=pitch L4). That is, the pitch of the transport boxes 520 are set to L4, at which the inner halves of adjacent transport boxes 520 do not interfere (i.e., are not in contact) with one another in the curved portions of the guide rail 550.
The transport articles 5101 which are transported in each transport box 520 are discharged into predetermined stackers 5113 in the section frames 5111 for different destinations, respectively. In other words, the transporter/sorter 500 sorts out the transport articles 5101 during transport thereof for different destinations, respectively.
Another example of a conventional transporter/sorter will be described with reference to FIGS. 25-27.
FIG. 25a is a schematic plan view of a conventional transporter/sorter and FIG. 25b is a schematic front view of such transporter/sorter.
In FIGS. 25a and 25b, the prior art transporter/sorter 500 comprises a frame 510, a guide rail 550 of an endless loop having straight portions and curved portions and also provided in the frame 5110, and a plurality of transport boxes 520 depending from the guide rail 550 so as to travel in circulation along the endless loop path.
The frame 5110 comprises a plurality of section frames 5111 and four feeder frames 5112. The section frames 5111 are provided with a plurality of stackers 5113 for stacking transport articles 5101 discharged from the transport boxes 520. On the other hand, the feeder frames 5112 comprise feeder frames 512 for feeding stacked transport articles 5101 one by one, belts 514 for transporting the fed transport articles 5101, and feeding means 513 for transporting the fed transport articles 5101 to the transport boxes 520.
It is to be noted that the stackers 5113 and the feeding means 513 are generally disposed at the straight transport portions for the transport boxes 520. The transport articles 5101 maybe post cards, documents, magazines, books, CD cases, etc., but not limited thereto.
FIG. 26a is a schematic front view of the prior art transport box, while FIG. 26b is a schematic side view of the prior art transport box as seen from the outside thereof.
In FIGS. 26a and 26b, the transport box 520 is a generally rectangular box and comprises four accommodating chambers 5121 divided by partitioning plates 5122 at an equal spacing. As best shown in FIG. 26b, the transport box 520 is a parallelogram that is projecting in the transport direction at the top as seen from the side. With this arrangement, the transport articles 5101 can be discharged smoothly.
Additionally, the transport box 520 is depending from the guide rail 550 by way of inter-coupled transport wagons (not shown). The transport boxes 520 are supported onto the guide rail 550 in such a manner that the center of gravity of each transport box 520 is immediately below the guide rail 550 as seen from the top.
Each of the transport boxes 520 is formed with a feeding port 5123 on the side face in the outer direction through which the transport articles may be thrown.
Each of the accommodating chambers 5121 is made to have a constant width W in the transport direction over the entire area as seen from the front. Accordingly, the width in the transport direction of the feeding space 5124 which is used when the transport articles 5101 are fed is also W (constant) over the entire area as seen from the front.
The transport boxes 520 are formed with a revolving bottom lid 518 at the bottom of each accommodating chamber 5121 as discharging means for the transport articles 5101.
The bottom lid 518 is pivotally supported at both ends in such a manner that the bottom lid 518 is in the open state (see the solid arrow in FIG. 26b) by spring bias of a coil spring 581. On the other hand, the bottom lid 518 is kept in the closed state by engagement of a notch 582 with an engaging plate 583 when it is closed.
Also, the engagement plate 583 is coupled to an abutment plate 584 which is pivotally supported in a biased in the closed state (see the dotted arrow in FIG. 26b) by an elastic member such as a coil spring or the like (not shown).
The bottom lid 518 is arranged so that, when the transport box 520 is transported over a predetermined stacker 5113, a pin 586 of a solenoid 585 (see FIG. 26a) disposed in the inward orientation projects for a short time, thereby allowing the abutment plate 584 to revolve. Such revolution also allows the engagement plate 583 to revolve, thereby opening the biased bottom lid 518 and maintaining such state.
Moreover, when the transport box 520 passes the last stacker 5113, the bottom lid 518 in the open state is in contact with a bottom plate (not shown) disposed at the lower portion of the transport box 520, thereby revolving the bottom lid 518 in the closing direction. When the bottom lid 518 is closed, the notch 582 engages with the engagement plate 583 and the bottom lid 518 remains in the closed state.
It is to be noted, however, that the discharging means is not limited to the above configuration comprising the bottom lid 518.
As shown in FIG. 27, the feeding means 513 comprises, for example, two belts 5132, 5133 which run over a plurality of rollers 5134 for transporting the transport articles 101 therebetween, a roller 5135 provided at the end portion in the transport direction, and swinging means (not shown) for swinging the feeding means 513 in response to the transport speed and timing of the transport box 520. With this arrangement, since the feeding means 513 swings the transport box 520 in harmonize with the transport speed and timing of the transport box 520, it is possible to extend the feeding time (from the start of feeding to the completion of feeding).
Now, the operation of the transporter/sorter 500 as sown in FIGS. 25-27 will be described.
The transporter/sorter 500 transports the transport articles 5101 which are fed by the belts 514 of the feeder 512 one by one to the feeding means 513. Then, the feeding means 513 feeds the transport articles 5101 to the predetermined accommodating chamber 5121. It is to be noted that, in general, the most upstream (or a first) feeding means 513 feeds the transport articles 5101 to the leading (or a first) accommodating chamber 5121 in the transport direction. Then, the subsequently downstream (second, third and fourth) feeding means 513 feed the transport articles 5101 to the sequential (second, third and fourth) accommodating chambers 5121.
FIG. 27 is cross section views seen from the top for describing the feeding operation of the prior art feeding means, wherein FIG. 27(a) is a schematic view when the feeding is started, FIG. 27(b) is a schematic view on the half way of feeding operation, FIG. 27(c) is a schematic view when the feeding operation has been completed and FIG. 27(d) is a schematic when it is in preparation for feeding.
In FIG. 27(a), the feeding means 513 swings by the swinging means in such a manner that the velocity component at the end portion where the transport articles 5101 are pushed out is substantially equal to the transport speed of the transport box 520. And the transport articles 5101 are fed by the two belts 5132, 5133. It is to be noted that the feeding start time is when a leading end of a transport article 5101 reaches the feeding port 5123.
Then, in FIG. 27(b), the feeding means 513 continues to swing, thereby feeding the transport article 5101 into the feeding space 5124 in the accommodating chamber 5121. As shown in FIG. 27(c), the feeding means 513 continues to swing and feeding until the tail end of the transport article 101 reaches the feeding port 5123. The completion time of feeding is the time when the tail end of the transport article 5101 has reached the (the last) feeding port 5123.
Upon completion of the feeding, the feeding means 513 decreases the swinging speed and stops. Subsequently, the feeding means 513 swings in the opposite (returning) direction and stops to resume the ready condition in preparation for the next feeding as shown in FIG. 27(d).
It is to be noted that the transport articles 5101 are thrown into the feeding spaces 5124 from the feeding ports 5123 in substantially horizontal direction and fall downward by colliding with inner side plates 5125. And the fallen transport articles 5101 are clamped by the outer side plate 5126 (see FIG. 26b) so that they do not jump out of the feeding ports 5123.
Then, the transporter/sorter 500 transport the transport boxes 520 in which the transport articles 5101 are fed along the guide rail 550 to the section frames 5111 by driving means (not shown) And the transporter/sorter 500 opens the bottom lids 518 for discharging the transport articles 5101 into the respective stackers 5113 depending on their destinations. That is, the transporter/sorter 500 can classify the transport articles 5101 to their destinations while being transported.
Incidentally, let the width of each accommodating chamber 5121 in the transport direction be W and the thickness of the transport article 5101 in the transport direction be t as shown in FIG. 26b, the gap Δ of the feeding spaces 5124 in the transport direction is Δ=W−t (mm).
Transport density of the transport boxes 520 is given by t/W (%) on the assumption that the thickness of the partitioning plates 5122 is negligible small.
Furthermore, the feeding time required for stably feeding the transport articles 5101 is proportional to Δ and counter proportional to the transport speed v of the transport boxes 520.
As understood from the above relationship, if the transport density is increased in order to improve the transport capacity of the transport boxes 520, Δ decreases and thus reducing the feeding time, thereby decreasing feeding stability. Similarly, if the transport speed v is increased in order to improve the processing capacity of the transporter/sorter 500, Δ decreases and thus reducing the feeding time, thereby decreasing feeding stability.
On the other hand, if the feeding speed of the feeding means 513 is made constant, since the feeding time increases as the length of the transport article 5101 in the feeding direction becomes longer, it is necessary to increase the gap Δ in the transport direction or decrease the transport speed v.
Since the transporter/sorter 500 can improve processing capacity by increasing the transport density, various techniques have been developed. Japanese patent publication no. 2003-237926 discloses techniques of a transporter/sorter of variable transport box pitch type.
In this transporter/sorter, a transport box pitch varying mechanism for varying the pitch of transport boxes is provided at the boundaries between straight and curved portions of an endless loop path. The density of mounting of transport boxes in the straight portions thus can be increased, and the transfer speed in the straight portions can be held at a minimum necessary value. With this arrangement, without reduction of the transport article processing capacity, it is possible to ensure stable operations of feeding and discharging transport articles.
Although the variable pitch type transporter/sorter could increase the processing capacity by realizing higher transport density at the straight portions, the market demands are to provide further improvement on the processing capacity. However, in the high density transport, the adjacent transport boxes are almost in contact with one another. In order to further increase the processing capacity of the transporter/sorter, it is required to reduce the gap Δ of the accommodating chambers in the transport direction or to increase the transport speed v of the transport boxes.
However, the prior art transporters/sorters as described hereinabove have the following problems.
In the prior art transporter/sorter 500 shown in FIGS. 22(a), 22(b) and 23, the transport wagons 530 undergoing excursion along the endless loop path hang the transport boxes 520 at the top center part thereof at a constant interval for the transport of the transport boxes 520. While the minimum pitch L4 is set, at which adjacent transport boxes 520 do not interfere with one another in the curved portions of the endless loop path of the transporter/sorter 500, in the straight portions the pitch L3 of the transport boxes 520 includes a large gap. This means a sacrifice given to the straight portions with respect to the efficiency of mounting the transport boxes 520, i.e., the transport density. That is, it is impossible to improve the processing capacity of the transport articles 5101 or ensure stable processing operation.
Also, in the transporter/sorter 500 the number of transport articles 5101 processed per unit time depends on the transfer speed of the transport wagons 530. That is, the processing number can be increased depending on the transport speed. However, the transporter/sorter 500 has a drawback that increasing the transport speed gives rise to unstable operations of feeding (i.e., throwing) and discharging transport articles 5101, executed with respect to the transport boxes 520 being transferred, thus leading to reliability deterioration in the operation of processing the transport articles 5101.
As a further drawback of the transporter/sorter 500, reducing the transfer speed to make stable the operations of feeding and discharging the transport articles 5101, reduces efficiency of mounting the transport boxes 520 in the straight portions, thus reducing the unit time process capacity of the transporter/sorter 500.
The transporter/sorter as shown in FIGS. 25-27 has a drawback that the transport articles tend to contact with the partitioning plates of the accommodating chambers at the opposite sides to the transport direction before completion of feeding of the transport articles if the gap Δ in the transport direction between the adjacent accommodating chambers in the transport box is reduced or if the transport speed v of the transport boxes of the transporter/sorter is increased, thereby causing unstable feeding or failure of feeding.
Particularly, if the transport articles become larger in the feeding direction, the feeding time becomes longer. The extended feeding time is a bottleneck for improving the processing capacity of the transporter/sorter.
On the other hand, the transporter/sorter of variable transport box pitch type as disclosed in the above patent publication has a problem that the transport box pitch varying mechanism is complicated in arrangement and control, and therefore it is impossible to reduce, for instance, the cost of manufacture.